// Copyright 2023 The Dawn & Tint Authors
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this
//    list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice,
//    this list of conditions and the following disclaimer in the documentation
//    and/or other materials provided with the distribution.
//
// 3. Neither the name of the copyright holder nor the names of its
//    contributors may be used to endorse or promote products derived from
//    this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

package node

import (
	"context"
	"flag"
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
	"runtime"
	"strings"

	"dawn.googlesource.com/dawn/tools/src/cmd/run-cts/common"
	"dawn.googlesource.com/dawn/tools/src/cov"
	"dawn.googlesource.com/dawn/tools/src/fileutils"
	"dawn.googlesource.com/dawn/tools/src/subcmd"
)

type dawnFlags []string

func (f *dawnFlags) String() string {
	return strings.Join(*f, "")
}

func (f *dawnFlags) Set(value string) error {
	// Multiple flags must be passed in individually:
	// -flag=a=b -dawn_node_flag=c=d
	*f = append(*f, value)
	return nil
}

// Consolidates all the delimiter separated flags with a given prefix into a single flag.
// Example:
// Given the flags: ["foo=a", "bar", "foo=b,c"]
// GlobListFlags("foo=", ",") will transform the flags to: ["bar", "foo=a,b,c"]
func (f *dawnFlags) GlobListFlags(prefix string, delimiter string) {
	list := []string{}
	i := 0
	for _, flag := range *f {
		if strings.HasPrefix(flag, prefix) {
			// Trim the prefix.
			value := flag[len(prefix):]
			// Extract the deliminated values.
			list = append(list, strings.Split(value, delimiter)...)
		} else {
			(*f)[i] = flag
			i++
		}
	}
	(*f) = (*f)[:i]
	if len(list) > 0 {
		// Append back the consolidated flags.
		f.Set(prefix + strings.Join(list, delimiter))
	}
}

// defaultBinPath looks for the binary output directory at <dawn>/out/active.
// This is used as the default for the --bin command line flag.
func defaultBinPath() string {
	if dawnRoot := fileutils.DawnRoot(); dawnRoot != "" {
		bin := filepath.Join(dawnRoot, "out/active")
		if info, err := os.Stat(bin); err == nil && info.IsDir() {
			return bin
		}
	}
	return ""
}

type flags struct {
	common.Flags
	bin                  string
	backend              string
	adapterName          string
	coverageFile         string
	isolated             bool
	build                bool
	validate             bool
	dumpShaders          bool
	fxc                  bool
	unrollConstEvalLoops bool
	genCoverage          bool
	compatibilityMode    bool
	skipVSCodeInfo       bool
	dawn                 dawnFlags
}

func init() {
	common.Register(&cmd{})
}

type cmd struct {
	state    common.State
	flags    flags
	coverage *common.Coverage
	query    string
}

func (cmd) IsDefaultCommand() {}

func (cmd) Name() string {
	return "node"
}

func (cmd) Desc() string {
	return "runs the CTS with dawn.node"
}

func (c *cmd) RegisterFlags(ctx context.Context, cfg common.Config) ([]string, error) {
	unrollConstEvalLoopsDefault := runtime.GOOS != "windows"

	backendDefault := "default"
	if vkIcdFilenames := os.Getenv("VK_ICD_FILENAMES"); vkIcdFilenames != "" {
		backendDefault = "vulkan"
	}

	c.flags.Flags.Register()
	flag.StringVar(&c.flags.bin, "bin", defaultBinPath(), "path to the directory holding cts.js and dawn.node")
	flag.BoolVar(&c.flags.isolated, "isolate", false, "run each test in an isolated process")
	flag.BoolVar(&c.flags.build, "build", true, "attempt to build the CTS before running")
	flag.BoolVar(&c.flags.validate, "validate", false, "enable backend validation")
	flag.Var(&c.flags.dawn, "flag", "flag to pass to dawn-node as flag=value. multiple flags must be passed in individually")
	flag.StringVar(&c.flags.backend, "backend", backendDefault, "backend to use: default|null|webgpu|d3d11|d3d12|metal|vulkan|opengl|opengles."+
		" set to 'vulkan' if VK_ICD_FILENAMES environment variable is set, 'default' otherwise")
	flag.StringVar(&c.flags.adapterName, "adapter", "", "name (or substring) of the GPU adapter to use")
	flag.BoolVar(&c.flags.dumpShaders, "dump-shaders", false, "dump WGSL shaders. Enables --verbose")
	flag.BoolVar(&c.flags.fxc, "fxc", false, "Use FXC instead of DXC. Disables 'use_dxc' Dawn flag")
	flag.BoolVar(&c.flags.unrollConstEvalLoops, "unroll-const-eval-loops", unrollConstEvalLoopsDefault, "unroll loops in const-eval tests")
	flag.BoolVar(&c.flags.genCoverage, "coverage", false, "displays coverage data")
	flag.StringVar(&c.flags.coverageFile, "export-coverage", "", "write coverage data to the given path")
	flag.BoolVar(&c.flags.compatibilityMode, "compat", false, "run tests in compatibility mode")
	flag.BoolVar(&c.flags.skipVSCodeInfo, "skip-vs-code-info", false, "skips emitting VS Code information")

	return []string{"[query]"}, nil
}

func (c *cmd) Run(ctx context.Context, cfg common.Config) error {
	// Process the command line flags
	if err := c.processFlags(); err != nil {
		return err
	}

	if err := c.maybeInitCoverage(); err != nil {
		return err
	}

	if err := c.state.CTS.Node.BuildIfRequired(c.flags.Verbose); err != nil {
		return err
	}

	// Find all the test cases that match r.query.
	testCases, err := c.state.CTS.QueryTestCases(c.flags.Verbose, c.query)
	if err != nil {
		return fmt.Errorf("failed to gather tests: %w", err)
	}
	fmt.Printf("Testing %d test cases...\n", len(testCases))

	var runner func(ctx context.Context, testCases []common.TestCase, results chan<- common.Result)
	if c.flags.isolated {
		fmt.Println("Running in parallel isolated...")
		runner = c.runTestCasesWithCmdline
	} else {
		fmt.Println("Running in parallel with server...")
		runner = c.runTestCasesWithServers
	}

	resultStream := make(chan common.Result, 256)
	go func() {
		runner(ctx, testCases, resultStream)
		close(resultStream)
	}()

	results, err := common.StreamResults(ctx,
		c.flags.Colors,
		c.state,
		c.flags.Verbose,
		c.coverage,
		len(testCases),
		resultStream)
	if err != nil {
		return err
	}

	if err := c.state.Close(results); err != nil {
		return err
	}

	return nil
}

func (c *cmd) processFlags() error {
	// Check mandatory arguments
	if c.flags.bin == "" {
		return subcmd.InvalidCLA()
	}
	if !fileutils.IsDir(c.flags.bin) {
		return fmt.Errorf("'%v' is not a directory", c.flags.bin)
	}
	for _, file := range []string{"cts.js", "dawn.node"} {
		if !fileutils.IsFile(filepath.Join(c.flags.bin, file)) {
			return fmt.Errorf("'%v' does not contain '%v'", c.flags.bin, file)
		}
	}

	// Make paths absolute
	absBin, err := filepath.Abs(c.flags.bin)
	if err != nil {
		return fmt.Errorf("unable to get absolute path for '%v'", c.flags.bin)
	}
	c.flags.bin = absBin

	// The test query is the optional unnamed argument
	c.query = "webgpu:*"
	switch len(flag.Args()) {
	case 0:
	case 1:
		c.query = flag.Args()[0]
	default:
		return fmt.Errorf("only a single query can be provided")
	}

	// For Windows, set the DLL directory to bin so that Dawn loads dxcompiler.dll from there.
	c.flags.dawn.Set("dlldir=" + c.flags.bin)

	// Forward the backend and adapter to use, if specified.
	if c.flags.backend != "default" {
		fmt.Println("Forcing backend to", c.flags.backend)
		c.flags.dawn.Set("backend=" + c.flags.backend)
	}
	if c.flags.adapterName != "" {
		c.flags.dawn.Set("adapter=" + c.flags.adapterName)
	}
	if c.flags.validate {
		c.flags.dawn.Set("validate=1")
	}

	// While running the CTS, always allow unsafe APIs so they can be tested.
	c.flags.dawn.Set("enable-dawn-features=allow_unsafe_apis")
	if c.flags.dumpShaders {
		c.flags.Verbose = true
		c.flags.dawn.Set("enable-dawn-features=dump_shaders,disable_symbol_renaming")
	}
	if c.flags.fxc {
		c.flags.dawn.Set("disable-dawn-features=use_dxc")
	}
	c.flags.dawn.GlobListFlags("enable-dawn-features=", ",")

	state, err := c.flags.Process()
	if err != nil {
		return err
	}
	c.state = *state

	return nil
}

func (c *cmd) maybeInitCoverage() error {
	if !c.flags.genCoverage && c.flags.coverageFile == "" {
		return nil
	}

	profdata, err := exec.LookPath("llvm-profdata")
	if err != nil {
		profdata = ""
		if runtime.GOOS == "darwin" {
			profdata = "/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/llvm-profdata"
			if !fileutils.IsExe(profdata) {
				profdata = ""
			}
		}
	}
	if profdata == "" {
		return fmt.Errorf("failed to find llvm-profdata, required for --coverage")
	}

	llvmCov := ""
	turboCov := filepath.Join(c.flags.bin, "turbo-cov"+fileutils.ExeExt)
	if !fileutils.IsExe(turboCov) {
		turboCov = ""
		if path, err := exec.LookPath("llvm-cov"); err == nil {
			llvmCov = path
		} else {
			return fmt.Errorf("failed to find turbo-cov or llvm-cov")
		}
	}
	c.coverage = &common.Coverage{
		OutputFile: c.flags.coverageFile,
		Env: &cov.Env{
			Profdata: profdata,
			Binary:   filepath.Join(c.flags.bin, "dawn.node"),
			Cov:      llvmCov,
			TurboCov: turboCov,
		},
	}

	return nil
}