package manifest

import (
	"errors"
	"fmt"
	"os"
	"path/filepath"
	"strings"

	"github.com/BurntSushi/toml"

	"gitea.lclr.dev/AI/mcp-framework/update"
)

const DefaultFile = "mcp.toml"

type File struct {
	BinaryName  string      `toml:"binary_name"`
	DocsURL     string      `toml:"docs_url"`
	Update      Update      `toml:"update"`
	Build       Build       `toml:"build"`
	Environment Environment `toml:"environment"`
	SecretStore SecretStore `toml:"secret_store"`
	Profiles    Profiles    `toml:"profiles"`
	Bootstrap   Bootstrap   `toml:"bootstrap"`
}

type Update struct {
	SourceName        string   `toml:"source_name"`
	Driver            string   `toml:"driver"`
	Repository        string   `toml:"repository"`
	BaseURL           string   `toml:"base_url"`
	LatestReleaseURL  string   `toml:"latest_release_url"`
	AssetNameTemplate string   `toml:"asset_name_template"`
	ChecksumAssetName string   `toml:"checksum_asset_name"`
	ChecksumRequired  bool     `toml:"checksum_required"`
	TokenHeader       string   `toml:"token_header"`
	TokenPrefix       string   `toml:"token_prefix"`
	TokenEnvNames     []string `toml:"token_env_names"`
}

type Build struct {
	MainPackage string        `toml:"main_package"`
	OutputDir   string        `toml:"output_dir"`
	VersionVar  string        `toml:"version_var"`
	Targets     []BuildTarget `toml:"targets"`
}

type BuildTarget struct {
	OS   string `toml:"os"`
	Arch string `toml:"arch"`
}

type Environment struct {
	Known []string `toml:"known"`
}

type SecretStore struct {
	BackendPolicy string `toml:"backend_policy"`
}

type Profiles struct {
	Default string   `toml:"default"`
	Known   []string `toml:"known"`
}

type Bootstrap struct {
	Description string `toml:"description"`
}

type BootstrapMetadata struct {
	BinaryName     string
	Description    string
	DocsURL        string
	DefaultProfile string
	Profiles       []string
}

type ScaffoldMetadata struct {
	BinaryName                string
	DocsURL                   string
	KnownEnvironmentVariables []string
	SecretStorePolicy         string
	DefaultProfile            string
	Profiles                  []string
}

func Find(startDir string) (string, error) {
	dir := strings.TrimSpace(startDir)
	if dir == "" {
		wd, err := os.Getwd()
		if err != nil {
			return "", fmt.Errorf("resolve working directory: %w", err)
		}
		dir = wd
	}

	absDir, err := filepath.Abs(dir)
	if err != nil {
		return "", fmt.Errorf("resolve manifest search path %q: %w", dir, err)
	}

	for {
		path := filepath.Join(absDir, DefaultFile)
		info, err := os.Stat(path)
		switch {
		case err == nil:
			if info.IsDir() {
				return "", fmt.Errorf("manifest path %q is a directory", path)
			}
			return path, nil
		case !errors.Is(err, os.ErrNotExist):
			return "", fmt.Errorf("stat manifest %q: %w", path, err)
		}

		parent := filepath.Dir(absDir)
		if parent == absDir {
			return "", fmt.Errorf("find manifest %q from %q: %w", DefaultFile, dir, os.ErrNotExist)
		}
		absDir = parent
	}
}

func Load(path string) (File, error) {
	data, err := os.ReadFile(path)
	if err != nil {
		return File{}, fmt.Errorf("read manifest %s: %w", path, err)
	}

	var file File
	if err := toml.Unmarshal(data, &file); err != nil {
		return File{}, fmt.Errorf("parse manifest %s: %w", path, err)
	}

	file.normalize()
	return file, nil
}

func LoadDefault(startDir string) (File, string, error) {
	path, err := Find(startDir)
	if err != nil {
		return File{}, "", err
	}

	file, err := Load(path)
	if err != nil {
		return File{}, "", err
	}

	return file, path, nil
}

func (f *File) normalize() {
	f.BinaryName = strings.TrimSpace(f.BinaryName)
	f.DocsURL = strings.TrimSpace(f.DocsURL)
	f.Update.normalize()
	f.Build.normalize()
	f.Environment.normalize()
	f.SecretStore.normalize()
	f.Profiles.normalize()
	f.Bootstrap.normalize()
}

func (u *Update) normalize() {
	u.SourceName = strings.TrimSpace(u.SourceName)
	u.Driver = strings.ToLower(strings.TrimSpace(u.Driver))
	u.Repository = strings.Trim(strings.TrimSpace(u.Repository), "/")
	u.BaseURL = strings.TrimRight(strings.TrimSpace(u.BaseURL), "/")
	u.LatestReleaseURL = strings.TrimSpace(u.LatestReleaseURL)
	u.AssetNameTemplate = strings.TrimSpace(u.AssetNameTemplate)
	u.ChecksumAssetName = strings.TrimSpace(u.ChecksumAssetName)
	u.TokenHeader = strings.TrimSpace(u.TokenHeader)
	u.TokenPrefix = strings.TrimSpace(u.TokenPrefix)
	u.TokenEnvNames = normalizeStringList(u.TokenEnvNames)
}

func (b *Build) normalize() {
	b.MainPackage = strings.TrimSpace(b.MainPackage)
	b.OutputDir = strings.TrimSpace(b.OutputDir)
	b.VersionVar = strings.TrimSpace(b.VersionVar)
	b.Targets = normalizeBuildTargets(b.Targets)
}

func (e *Environment) normalize() {
	e.Known = normalizeStringList(e.Known)
}

func (s *SecretStore) normalize() {
	s.BackendPolicy = strings.TrimSpace(s.BackendPolicy)
}

func (p *Profiles) normalize() {
	p.Default = strings.TrimSpace(p.Default)
	p.Known = normalizeStringList(p.Known)
}

func (b *Bootstrap) normalize() {
	b.Description = strings.TrimSpace(b.Description)
}

func (u Update) ReleaseSource() update.ReleaseSource {
	u.normalize()

	return update.ReleaseSource{
		Name:              u.SourceName,
		Driver:            u.Driver,
		Repository:        u.Repository,
		BaseURL:           u.BaseURL,
		LatestReleaseURL:  u.LatestReleaseURL,
		AssetNameTemplate: u.AssetNameTemplate,
		ChecksumAssetName: u.ChecksumAssetName,
		ChecksumRequired:  u.ChecksumRequired,
		TokenHeader:       u.TokenHeader,
		TokenPrefix:       u.TokenPrefix,
		TokenEnvNames:     append([]string(nil), u.TokenEnvNames...),
	}
}

func (f File) BootstrapInfo() BootstrapMetadata {
	f.normalize()

	return BootstrapMetadata{
		BinaryName:     f.BinaryName,
		Description:    f.Bootstrap.Description,
		DocsURL:        f.DocsURL,
		DefaultProfile: f.Profiles.Default,
		Profiles:       append([]string(nil), f.Profiles.Known...),
	}
}

func (f File) ScaffoldInfo() ScaffoldMetadata {
	f.normalize()

	return ScaffoldMetadata{
		BinaryName:                f.BinaryName,
		DocsURL:                   f.DocsURL,
		KnownEnvironmentVariables: append([]string(nil), f.Environment.Known...),
		SecretStorePolicy:         f.SecretStore.BackendPolicy,
		DefaultProfile:            f.Profiles.Default,
		Profiles:                  append([]string(nil), f.Profiles.Known...),
	}
}

func normalizeStringList(values []string) []string {
	normalized := values[:0]
	for _, value := range values {
		if trimmed := strings.TrimSpace(value); trimmed != "" {
			normalized = append(normalized, trimmed)
		}
	}
	return normalized
}

func normalizeBuildTargets(values []BuildTarget) []BuildTarget {
	if len(values) == 0 {
		return values
	}

	normalized := values[:0]
	seen := make(map[string]struct{}, len(values))
	for _, value := range values {
		target := BuildTarget{
			OS:   strings.ToLower(strings.TrimSpace(value.OS)),
			Arch: strings.ToLower(strings.TrimSpace(value.Arch)),
		}
		if target.OS == "" || target.Arch == "" {
			continue
		}

		key := target.OS + "/" + target.Arch
		if _, exists := seen[key]; exists {
			continue
		}
		seen[key] = struct{}{}
		normalized = append(normalized, target)
	}

	return normalized
}