package main

import (
    "fmt"
    "net/url"
    "strings"
)

// configuration holds the plugin settings from the System Console.
type configuration struct {
    OllamaURL          string
    DefaultModel       string
    SystemPrompt       string
    MaxTokens          int
    RateLimitPerMinute int
    AllowedUserIDs     string
    StopWords          string
}

// getConfiguration returns the current configuration, safe for concurrent use.
func (p *Plugin) getConfiguration() *configuration {
    p.configLock.RLock()
    defer p.configLock.RUnlock()
    return p.configuration
}

// setConfiguration updates the configuration and validates it.
func (p *Plugin) setConfiguration(c *configuration) error {
    p.configLock.Lock()
    defer p.configLock.Unlock()

    if c == nil {
        return fmt.Errorf("nil configuration")
    }

    if err := c.validate(); err != nil {
        return fmt.Errorf("invalid configuration: %w", err)
    }

    p.configuration = c
    return nil
}

// validate checks that the configuration values are usable.
func (c *configuration) validate() error {
    if c.OllamaURL == "" {
        return fmt.Errorf("OllamaURL must not be empty")
    }
    u, err := url.Parse(c.OllamaURL)
    if err != nil {
        return fmt.Errorf("OllamaURL is not a valid URL: %w", err)
    }
    if u.Scheme != "http" && u.Scheme != "https" {
        return fmt.Errorf("OllamaURL must use http or https scheme, got %q", u.Scheme)
    }
    if c.DefaultModel == "" {
        return fmt.Errorf("DefaultModel must not be empty")
    }
    if c.MaxTokens < 0 {
        return fmt.Errorf("MaxTokens must not be negative")
    }
    if c.RateLimitPerMinute < 0 {
        return fmt.Errorf("RateLimitPerMinute must not be negative")
    }
    return nil
}

// OnConfigurationChange is called by the Mattermost server when the plugin
// configuration is changed in the System Console.
func (p *Plugin) OnConfigurationChange() error {
    var c configuration

    // Load from the System Console settings.
    if err := p.API.LoadPluginConfiguration(&c); err != nil {
        return fmt.Errorf("failed to load plugin configuration: %w", err)
    }

    if err := p.setConfiguration(&c); err != nil {
        return fmt.Errorf("failed to set configuration: %w", err)
    }

    return nil
}

// allowedUsers returns the set of user IDs allowed to use the plugin.
// An empty set means all users are allowed.
func (c *configuration) allowedUsers() map[string]bool {
    if strings.TrimSpace(c.AllowedUserIDs) == "" {
        return nil
    }
    users := make(map[string]bool)
    for _, id := range strings.Split(c.AllowedUserIDs, ",") {
        users[strings.TrimSpace(id)] = true
    }
    return users
}

// stopWordSet returns the set of stop words for the engagement engine.
func (c *configuration) stopWordSet() map[string]bool {
    if strings.TrimSpace(c.StopWords) == "" {
        return map[string]bool{
            "thanks": true, "thank you": true, "bye": true,
            "goodbye": true, "that's all": true, "done": true,
            "stop": true, "quit": true, "end": true,
        }
    }
    words := make(map[string]bool)
    for _, w := range strings.Split(c.StopWords, ",") {
        words[strings.TrimSpace(strings.ToLower(w))] = true
    }
    return words
}