#include "Tracing.h"
#include "Bounds.h"
#include "Function.h"
#include "IRMutator.h"
#include "IROperator.h"
#include "RealizationOrder.h"
#include "runtime/HalideRuntime.h"

#include <set>

namespace Halide {
namespace Internal {

using std::map;
using std::pair;
using std::set;
using std::string;
using std::vector;

namespace {

struct TraceEventBuilder {
    string func;
    Expr trace_tag_expr = Expr("");
    vector<Expr> value;
    vector<Expr> coordinates;
    Type type;
    enum halide_trace_event_code_t event;
    Expr parent_id, value_index;

    Expr build() {
        Expr values = Call::make(type_of<void *>(), Call::make_struct,
                                 value, Call::Intrinsic);
        Expr coords = Call::make(type_of<int32_t *>(), Call::make_struct,
                                 coordinates, Call::Intrinsic);
        Expr idx = value_index;
        if (!idx.defined()) {
            idx = 0;
        }

        // Note: if these arguments are changed in any meaningful way,
        // VectorizeLoops will likely need attention; it does nontrivial
        // special-casing of this call to get appropriate results.
        vector<Expr> args = {Expr(func),
                             values, coords,
                             (int)type.code(), (int)type.bits(), (int)type.lanes(),
                             (int)event,
                             parent_id, idx, (int)coordinates.size(),
                             trace_tag_expr};
        return Call::make(Int(32), Call::trace, args, Call::Extern);
    }
};

class InjectTracing : public IRMutator {
public:
    const map<string, Function> &env;
    const bool trace_all_loads, trace_all_stores, trace_all_realizations;
    // We want to preserve the order, so use a vector<pair> rather than a map
    vector<pair<string, vector<string>>> trace_tags;
    set<string> trace_tags_added;
    // The funcs that will have any tracing info emitted (not just trace tags),
    // and the Type(s) of their elements.
    map<string, vector<Type>> funcs_touched;

    InjectTracing(const map<string, Function> &e, const Target &t)
        : env(e),
          trace_all_loads(t.has_feature(Target::TraceLoads)),
          trace_all_stores(t.has_feature(Target::TraceStores)),
          // Set trace_all_realizations to true if either trace_loads or trace_stores is on too:
          // They don't work without trace_all_realizations being on (and the errors are missing symbol mysterious nonsense).
          trace_all_realizations(t.features_any_of({Target::TraceLoads, Target::TraceStores, Target::TraceRealizations})) {
    }

private:
    void add_trace_tags(const string &name, const vector<string> &t) {
        if (!t.empty() && !trace_tags_added.count(name)) {
            trace_tags.emplace_back(name, t);
            trace_tags_added.insert(name);
        }
    }

    void add_func_touched(const string &name, int value_index, const Type &type) {
        auto it = funcs_touched.find(name);
        if (it == funcs_touched.end()) {
            vector<Type> types(value_index + 1);
            types[value_index] = type;
            funcs_touched[name] = types;
        } else {
            // If the type already present is missing, or "handle0" (aka "we don't know yet",
            // replace it with the given type. Otherwise, assert the types match.
            vector<Type> &types = it->second;
            if ((int)types.size() <= value_index) {
                types.resize(value_index + 1);
                types[value_index] = type;
            } else {
                internal_assert(type == Type() || type == types[value_index])
                    << "Type was already specified as " << types[value_index]
                    << " but now is " << type;
            }
        }
    }

    using IRMutator::visit;

    Expr visit(const Call *op) override {
        Expr expr = IRMutator::visit(op);
        op = expr.as<Call>();
        internal_assert(op);
        bool trace_it = false;
        Expr trace_parent;
        if (op->call_type == Call::Halide) {
            auto it = env.find(op->name);
            internal_assert(it != env.end()) << op->name << " not in environment\n";
            Function f = it->second;
            internal_assert(!f.can_be_inlined() || !f.schedule().compute_level().is_inlined());

            trace_it = f.is_tracing_loads() || trace_all_loads;
            trace_parent = Variable::make(Int(32), op->name + ".trace_id");
            if (trace_it) {
                add_trace_tags(op->name, f.get_trace_tags());
            }
        } else if (op->call_type == Call::Image) {
            trace_it = trace_all_loads;
            // If there is a Function in the env named "name_im", assume that
            // this image is an ImageParam, so sniff that Function to see
            // if we want to trace loads on it. (This allows us to trace
            // loads on inputs without having to enable them globally.)
            auto it = env.find(op->name + "_im");
            if (it != env.end()) {
                Function f = it->second;
                // f could be scheduled and have actual loads from it (via ImageParam::in),
                // so only honor trace the loads if it is inlined.
                if ((f.is_tracing_loads() || trace_all_loads) &&
                    f.can_be_inlined() &&
                    f.schedule().compute_level().is_inlined()) {
                    trace_it = true;
                    add_trace_tags(op->name, f.get_trace_tags());
                }
            }

            trace_parent = Variable::make(Int(32), "pipeline.trace_id");
        }

        if (trace_it) {
            add_func_touched(op->name, op->value_index, op->type);

            string value_var_name = unique_name('t');
            Expr value_var = Variable::make(op->type, value_var_name);

            TraceEventBuilder builder;
            builder.func = op->name;
            builder.value = {value_var};
            builder.coordinates = op->args;
            builder.type = op->type;
            builder.event = halide_trace_load;
            builder.parent_id = trace_parent;
            builder.value_index = op->value_index;
            Expr trace = builder.build();

            expr = Let::make(value_var_name, op,
                             Call::make(op->type, Call::return_second,
                                        {trace, value_var}, Call::PureIntrinsic));
        }
        return expr;
    }

    Stmt visit(const Provide *op) override {
        Stmt stmt = IRMutator::visit(op);
        op = stmt.as<Provide>();
        internal_assert(op);

        map<string, Function>::const_iterator iter = env.find(op->name);
        if (iter == env.end()) {
            return stmt;
        }
        Function f = iter->second;
        internal_assert(!f.can_be_inlined() || !f.schedule().compute_level().is_inlined());

        if (f.is_tracing_stores() || trace_all_stores) {
            // Wrap each expr in a tracing call

            const vector<Expr> &values = op->values;
            vector<Expr> traces(op->values.size());

            TraceEventBuilder builder;
            builder.func = f.name();
            builder.coordinates = op->args;
            builder.event = halide_trace_store;
            builder.parent_id = Variable::make(Int(32), op->name + ".trace_id");
            for (size_t i = 0; i < values.size(); i++) {
                Type t = values[i].type();
                add_func_touched(f.name(), (int)i, t);
                string value_var_name = unique_name('t');
                Expr value_var = Variable::make(t, value_var_name);

                builder.type = t;
                builder.value_index = (int)i;
                builder.value = {value_var};
                Expr trace = builder.build();
                if (!is_const_one(op->predicate)) {
                    trace = Call::make(trace.type(), Call::if_then_else,
                                       {op->predicate, trace}, Call::PureIntrinsic);
                }

                traces[i] = Let::make(value_var_name, values[i],
                                      Call::make(t, Call::return_second,
                                                 {trace, value_var}, Call::PureIntrinsic));
            }

            // Lift the args out into lets so that the order of
            // evaluation is right for scatters. Otherwise the store
            // is traced before any loads in the index.
            vector<Expr> args = op->args;
            vector<pair<string, Expr>> lets;
            for (auto &arg : args) {
                if (!arg.as<Variable>() && !is_const(arg)) {
                    string name = unique_name('t');
                    lets.emplace_back(name, arg);
                    arg = Variable::make(arg.type(), name);
                }
            }

            stmt = Provide::make(op->name, traces, args, op->predicate);
            for (const auto &p : lets) {
                stmt = LetStmt::make(p.first, p.second, stmt);
            }
        }
        return stmt;
    }

    Stmt visit(const Realize *op) override {
        Stmt stmt = IRMutator::visit(op);
        op = stmt.as<Realize>();
        internal_assert(op);

        map<string, Function>::const_iterator iter = env.find(op->name);
        if (iter == env.end()) {
            return stmt;
        }
        Function f = iter->second;
        if (f.is_tracing_realizations() || trace_all_realizations) {
            add_trace_tags(op->name, f.get_trace_tags());
            for (size_t i = 0; i < op->types.size(); i++) {
                add_func_touched(op->name, i, op->types[i]);
            }

            // Throw a tracing call before and after the realize body
            TraceEventBuilder builder;
            builder.func = op->name;
            builder.parent_id = Variable::make(Int(32), "pipeline.trace_id");
            builder.event = halide_trace_begin_realization;
            for (const auto &bound : op->bounds) {
                builder.coordinates.push_back(bound.min);
                builder.coordinates.push_back(bound.extent);
            }

            // Begin realization returns a unique token to pass to further trace calls affecting this buffer.
            Expr call_before = builder.build();

            builder.event = halide_trace_end_realization;
            builder.parent_id = Variable::make(Int(32), op->name + ".trace_id");
            Expr call_after = builder.build();

            Stmt new_body = op->body;
            new_body = Block::make(new_body, Evaluate::make(call_after));
            new_body = LetStmt::make(op->name + ".trace_id", call_before, new_body);
            stmt = Realize::make(op->name, op->types, op->memory_type, op->bounds, op->condition, new_body);
            // Warning: 'op' may be invalid at this point
        } else if (f.is_tracing_stores() || f.is_tracing_loads()) {
            // We need a trace id defined to pass to the loads and stores
            Stmt new_body = op->body;
            new_body = LetStmt::make(op->name + ".trace_id", 0, new_body);
            stmt = Realize::make(op->name, op->types, op->memory_type, op->bounds, op->condition, new_body);
        }
        return stmt;
    }

    Stmt visit(const ProducerConsumer *op) override {
        Stmt stmt = IRMutator::visit(op);
        op = stmt.as<ProducerConsumer>();
        internal_assert(op);
        map<string, Function>::const_iterator iter = env.find(op->name);
        if (iter == env.end()) {
            return stmt;
        }
        Function f = iter->second;
        if (f.is_tracing_realizations() || trace_all_realizations) {
            // Throw a tracing call around each pipeline event
            TraceEventBuilder builder;
            builder.func = op->name;
            builder.parent_id = Variable::make(Int(32), op->name + ".trace_id");

            // Use the size of the pure step
            const vector<string> &f_args = f.args();
            for (int i = 0; i < f.dimensions(); i++) {
                Expr min = Variable::make(Int(32), f.name() + ".s0." + f_args[i] + ".min");
                Expr max = Variable::make(Int(32), f.name() + ".s0." + f_args[i] + ".max");
                Expr extent = (max + 1) - min;
                builder.coordinates.push_back(min);
                builder.coordinates.push_back(extent);
            }

            builder.event = (op->is_producer ? halide_trace_produce : halide_trace_consume);
            Expr begin_op_call = builder.build();

            builder.event = (op->is_producer ? halide_trace_end_produce : halide_trace_end_consume);
            Expr end_op_call = builder.build();

            Stmt new_body = Block::make(op->body, Evaluate::make(end_op_call));

            stmt = LetStmt::make(f.name() + ".trace_id", begin_op_call,
                                 ProducerConsumer::make(op->name, op->is_producer, new_body));
        }
        return stmt;
    }
};

class RemoveRealizeOverOutput : public IRMutator {
    using IRMutator::visit;
    const vector<Function> &outputs;

    Stmt visit(const Realize *op) override {
        for (const Function &f : outputs) {
            if (op->name == f.name()) {
                return mutate(op->body);
            }
        }
        return IRMutator::visit(op);
    }

public:
    RemoveRealizeOverOutput(const vector<Function> &o)
        : outputs(o) {
    }
};

}  // namespace

Stmt inject_tracing(Stmt s, const string &pipeline_name, bool trace_pipeline,
                    const map<string, Function> &env, const vector<Function> &outputs,
                    const Target &t) {
    Stmt original = s;
    InjectTracing tracing(env, t);

    // Add a dummy realize block for the output buffers
    for (const Function &output : outputs) {
        Region output_region;
        Parameter output_buf = output.output_buffers()[0];
        internal_assert(output_buf.is_buffer());
        for (int i = 0; i < output.dimensions(); i++) {
            string d = std::to_string(i);
            Expr min = Variable::make(Int(32), output_buf.name() + ".min." + d);
            Expr extent = Variable::make(Int(32), output_buf.name() + ".extent." + d);
            output_region.push_back(Range(min, extent));
        }
        s = Realize::make(output.name(), output.output_types(), MemoryType::Auto, output_region, const_true(), s);
    }

    // Inject tracing calls
    s = tracing.mutate(s);

    // Strip off the dummy realize blocks
    s = RemoveRealizeOverOutput(outputs).mutate(s);

    if (!s.same_as(original) || trace_pipeline || t.has_feature(Target::TracePipeline)) {
        // Add pipeline start and end events
        TraceEventBuilder builder;
        builder.func = pipeline_name;
        builder.event = halide_trace_begin_pipeline;
        builder.parent_id = 0;

        Expr pipeline_start = builder.build();

        builder.event = halide_trace_end_pipeline;
        builder.parent_id = Variable::make(Int(32), "pipeline.trace_id");
        Expr pipeline_end = builder.build();

        s = Block::make(s, Evaluate::make(pipeline_end));

        // All trace_tag events go at the start, immediately after begin_pipeline.
        // For a given realization/input/output, we output them in the order
        // we encounter them (which is to say, the order they were added); however,
        // we don't attempt to preserve a particular order between functions.
        for (const auto &trace_tags : tracing.trace_tags) {
            // builder.parent_id is already set correctly
            builder.func = trace_tags.first;  // func name
            builder.event = halide_trace_tag;
            // We must reverse-iterate to preserve order
            for (auto it = trace_tags.second.rbegin(); it != trace_tags.second.rend(); ++it) {
                user_assert(it->find('\0') == string::npos)
                    << "add_trace_tag() may not contain the null character.";
                builder.trace_tag_expr = Expr(*it);
                s = Block::make(Evaluate::make(builder.build()), s);
            }
        }

        builder.event = halide_trace_tag;

        vector<string> order = topological_order(outputs, env);

        // Compute boxes_touched and send a func_type_and_dim trace-tag for
        // everything that we actually touched, in topological order.
        // We include the type(s) of each Func (could be multiple for Tuple-valued
        // Funcs), and the dimensions and guess-at-ranges-rouched. Note that the
        // dimensions should be exact, but the ranges-touched is a conservative estimate;
        // that's ok, as we just want to send these as rough guesses for a tracing tool to use for
        // automatic layout. (Note that we deliberately send these
        // before any user-specified trace-tags.)
        Expr space = Expr(" ");

        std::map<std::string, Box> bt = boxes_touched(s);
        for (auto topo_it = order.rbegin(); topo_it != order.rend(); ++topo_it) {
            const string &o = *topo_it;
            auto p = tracing.funcs_touched.find(*topo_it);
            if (p == tracing.funcs_touched.end() && ends_with(o, "_im")) {
                p = tracing.funcs_touched.find(o.substr(0, o.size() - 3));
            }
            if (p == tracing.funcs_touched.end()) {
                continue;
            }
            const string &func_name = p->first;
            const vector<Type> &func_types = p->second;
            builder.func = func_name;

            vector<Expr> strings;
            strings.emplace_back("func_type_and_dim:");
            strings.push_back(space);
            strings.emplace_back((int)func_types.size());
            for (const auto &func_type : func_types) {
                strings.push_back(space);
                strings.emplace_back((int)func_type.code());
                strings.push_back(space);
                strings.emplace_back(func_type.bits());
                strings.push_back(space);
                strings.emplace_back(func_type.lanes());
            }
            auto it = bt.find(func_name);
            internal_assert(it != bt.end());
            const Box &box = it->second;
            strings.push_back(space);
            strings.emplace_back((int)box.bounds.size());
            for (const Interval &i : box.bounds) {
                internal_assert(i.min.defined() && i.max.defined());
                if (i.is_bounded()) {
                    strings.push_back(space);
                    strings.push_back(i.min);
                    strings.push_back(space);
                    // Emit as (min, extent) rather than (min, max)
                    strings.push_back(i.max - i.min + Expr(1));
                } else {
                    // This should really only happen for unusual cases
                    // that we won't end up realizing, so we can just
                    // use any numeric values.
                    strings.push_back(space);
                    strings.emplace_back(0);
                    strings.push_back(space);
                    strings.emplace_back(0);
                }
            }
            builder.trace_tag_expr =
                Internal::Call::make(type_of<const char *>(),
                                     Internal::Call::stringify,
                                     strings,
                                     Internal::Call::PureIntrinsic);
            s = Block::make(Evaluate::make(builder.build()), s);
        }

        s = LetStmt::make("pipeline.trace_id", pipeline_start, s);
    }

    return s;
}

}  // namespace Internal
}  // namespace Halide
