package config

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

	"gitea.maximumdirect.net/eric/narratio/internal/fileops"
)

const maxPartyDocumentBytes = 8 << 20

func resolvePartyInput(input ResolvedInputFile) (ResolvedParty, error) {
	configuredPath := strings.TrimSpace(input.Path)
	if configuredPath == "" {
		return ResolvedParty{}, fmt.Errorf("party input path is required")
	}
	configPath := strings.TrimSpace(input.ConfigPath)
	if configPath == "" {
		return ResolvedParty{}, fmt.Errorf("party input %q has no declaring configuration path", configuredPath)
	}
	path := configuredPath
	if !filepath.IsAbs(path) {
		path = filepath.Join(filepath.Dir(configPath), path)
	}
	path = filepath.Clean(path)
	raw, err := fileops.ReadRegularFile(path, maxPartyDocumentBytes)
	if err != nil {
		return ResolvedParty{}, fmt.Errorf("read party input %q: %w", path, err)
	}
	document, err := ParseParty(raw)
	if err != nil {
		return ResolvedParty{}, fmt.Errorf("parse party input %q: %w", path, err)
	}
	resolved := ResolvedParty{
		Mode: document.Mode,
		Source: PartySource{
			Path:       path,
			ConfigPath: configPath,
			Source:     input.Source,
		},
		Canonical: document.Canonical,
	}
	if document.IsCanonical() {
		return resolved, nil
	}
	return resolveLegacyParty(resolved)
}

func campaignPartyInput(campaignPath string, campaign *CampaignConfig) (ResolvedInputFile, error) {
	if campaign == nil {
		return ResolvedInputFile{}, fmt.Errorf("campaign config is required")
	}
	if strings.TrimSpace(campaign.Inputs.PartyFile) == "" {
		return ResolvedInputFile{}, fmt.Errorf("campaign.inputs.party_file is required")
	}
	return ResolvedInputFile{
		Path:       campaign.Inputs.PartyFile,
		ConfigPath: campaignPath,
		Source:     "campaign_config",
	}, nil
}

func resolveCampaignParty(campaignPath string, campaign *CampaignConfig) (ResolvedParty, error) {
	input, err := campaignPartyInput(campaignPath, campaign)
	if err != nil {
		return ResolvedParty{}, err
	}
	return resolvePartyInput(input)
}

func validateCanonicalPartySelection(campaign *CampaignConfig, session *SessionConfig) error {
	if campaign == nil {
		return fmt.Errorf("campaign config is required")
	}
	if strings.TrimSpace(campaign.Inputs.PlayersFile) != "" {
		return fmt.Errorf("campaign.inputs.players_file is not allowed with a canonical party")
	}
	if session == nil {
		return nil
	}
	if strings.TrimSpace(session.Inputs.PlayersFile) != "" {
		return fmt.Errorf("session.inputs.players_file is not allowed with a canonical party")
	}
	if strings.TrimSpace(session.Inputs.PartyFile) != "" {
		return fmt.Errorf("session.inputs.party_file cannot override a canonical campaign party")
	}
	return nil
}

func virtualPlayersInput() ResolvedInputFile {
	return ResolvedInputFile{Source: "derived_from_party"}
}