package main

import (
	"encoding/json"
	"fmt"
	"os"
	"strings"

	"github.com/Mond1c/judge/dsl"
	"github.com/Mond1c/judge/reporter"
	"github.com/Mond1c/judge/runner"
)

const usage = `judge — CI/CD testing system for student solutions

Usage:
  judge <tests.jdg> <solution-dir> [flags]
  judge aggregate <reports-dir>

Flags:
  --json             output as JSON instead of text
  --wrapper <cmd>    exec wrapper (e.g. "valgrind --error-exitcode=99")
  --binary <name>    name of executable produced by build (overrides .jdg)
  --build <name>     run only the named structured build (use with matrix CI)
  --list-builds      print the names of structured builds in the suite as JSON
  --list-matrix      print the full (build, toolchain, platform) matrix as JSON
  --help             show help

Example:
  judge lab1.jdg ./student-solution
  judge lab1.jdg ./student-solution --json
  judge lab1.jdg ./student-solution --build=sanitized
  judge --list-builds lab1.jdg
  judge aggregate reports/
`

func main() {
	args := os.Args[1:]

	if len(args) == 0 || hasFlag(args, "--help") || hasFlag(args, "-h") {
		fmt.Print(usage)
		os.Exit(0)
	}

	if len(args) >= 1 && args[0] == "aggregate" {
		runAggregate(args[1:])
		return
	}

	if hasFlag(args, "--list-builds") {
		runListBuilds(args)
		return
	}

	if hasFlag(args, "--list-matrix") {
		runListMatrix(args)
		return
	}

	jsonOutput := hasFlag(args, "--json")
	wrapper := flagValue(args, "--wrapper")
	binary := flagValue(args, "--binary")
	targetBuild := flagValue(args, "--build")
	positional := positionalArgs(args)

	if len(positional) < 2 {
		fmt.Fprintf(os.Stderr, "error: need <tests.jdg> and <solution-dir>\n\n%s", usage)
		os.Exit(1)
	}

	testFile := positional[0]
	solutionDir := positional[1]

	f := parseSuite(testFile)

	if _, err := os.Stat(solutionDir); err != nil {
		fatalf("solution dir %q not found: %v", solutionDir, err)
	}

	r := runner.New(f, runner.Config{
		WorkDir:     solutionDir,
		BinaryName:  binary,
		Wrapper:     wrapper,
		TargetBuild: targetBuild,
	})
	result := r.Run()

	if jsonOutput {
		if err := reporter.JSON(os.Stdout, result); err != nil {
			fatalf("json output error: %v", err)
		}
	} else {
		reporter.Text(os.Stdout, result)
	}

	if result.TotalScore < 0.9999 {
		os.Exit(1)
	}
}

func parseSuite(path string) *dsl.File {
	src, err := os.ReadFile(path)
	if err != nil {
		fatalf("cannot read %q: %v", path, err)
	}
	f, warns, err := dsl.Parse(string(src))
	if err != nil {
		fatalf("parse error in %q:\n  %v", path, err)
	}
	for _, w := range warns {
		fmt.Fprintf(os.Stderr, "warning: %s\n", w)
	}
	return f
}

// runListBuilds prints a JSON array of build names for CI matrix discovery.
// A legacy suite without structured builds reports ["default"] so workflows
// can always iterate `fromJSON` and have exactly one cell.
func runListBuilds(args []string) {
	positional := positionalArgs(args)
	if len(positional) < 1 {
		fatalf("--list-builds requires the path to a .jdg file")
	}
	f := parseSuite(positional[0])

	var names []string
	if len(f.Builds) == 0 {
		names = []string{"default"}
	} else {
		for _, b := range f.Builds {
			names = append(names, b.Name)
		}
	}
	enc := json.NewEncoder(os.Stdout)
	if err := enc.Encode(names); err != nil {
		fatalf("encode list-builds: %v", err)
	}
}

type matrixEntry struct {
	Build     string `json:"build"`
	Toolchain string `json:"toolchain"`
	Platform  string `json:"platform"`
	Wrapper   string `json:"wrapper,omitempty"`
}

func runListMatrix(args []string) {
	positional := positionalArgs(args)
	if len(positional) < 1 {
		fatalf("--list-matrix requires the path to a .jdg file")
	}
	f := parseSuite(positional[0])

	var entries []matrixEntry

	if len(f.Builds) == 0 {
		if len(f.Toolchains) == 0 {
			entries = append(entries, matrixEntry{Build: "default", Toolchain: "default", Platform: "linux"})
		} else {
			for _, tc := range f.Toolchains {
				for _, platform := range tc.Platforms {
					entries = append(entries, matrixEntry{Build: "default", Toolchain: tc.Name, Platform: platform})
				}
			}
		}
	} else if len(f.Toolchains) == 0 {
		fatalf("suite has structured builds but no `toolchains { ... }` block; add one to use --list-matrix")
	} else {
		for _, b := range f.Builds {
			for _, tc := range f.Toolchains {
				for _, platform := range tc.Platforms {
					eff := b.Resolve(f.BuildDefaults, platform)
					if !eff.AppliesTo(platform, tc.Name) {
						continue
					}
					entries = append(entries, matrixEntry{
						Build:     b.Name,
						Toolchain: tc.Name,
						Platform:  platform,
						Wrapper:   eff.Wrapper,
					})
				}
			}
		}
	}

	enc := json.NewEncoder(os.Stdout)
	if err := enc.Encode(entries); err != nil {
		fatalf("encode list-matrix: %v", err)
	}
}

func runAggregate(args []string) {
	if len(args) < 1 {
		fatalf("usage: judge aggregate <reports-dir>")
	}
	if err := reporter.Aggregate(os.Stdout, args[0]); err != nil {
		fatalf("%v", err)
	}
}

func fatalf(msg string, args ...any) {
	fmt.Fprintf(os.Stderr, "error: "+msg+"\n", args...)
	os.Exit(1)
}

func hasFlag(args []string, name string) bool {
	for _, a := range args {
		if a == name {
			return true
		}
	}
	return false
}

func flagValue(args []string, name string) string {
	prefix := name + "="
	for i, a := range args {
		if a == name && i+1 < len(args) {
			return args[i+1]
		}
		if strings.HasPrefix(a, prefix) {
			return a[len(prefix):]
		}
	}
	return ""
}

func positionalArgs(args []string) []string {
	known := map[string]bool{
		"--json":        true,
		"--help":        true,
		"-h":            true,
		"--list-builds": true,
		"--list-matrix": true,
	}
	withValue := map[string]bool{
		"--wrapper": true,
		"--binary":  true,
		"--build":   true,
	}

	var out []string
	skip := false
	for _, a := range args {
		if skip {
			skip = false
			continue
		}
		if known[a] {
			continue
		}
		if withValue[a] {
			skip = true
			continue
		}
		if strings.HasPrefix(a, "--wrapper=") || strings.HasPrefix(a, "--binary=") || strings.HasPrefix(a, "--build=") {
			continue
		}
		out = append(out, a)
	}
	return out
}